Punching bag



FIG. 1 is a perspective view of a punching bag;

FIG. 2 is a front view thereof, the rear view being identical;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof; and,

FIG. 5 is a side view thereof, the opposite side being identical. 

CLAIM The ornamental design for a punching bag, as shown and described. 